The utility of ultrasound in detecting anterior compartment thickness changes in chronic exertional compartment syndrome: a pilot study.

Objective: To test the hypothesis that patients with chronic exertional compartment syndrome (CECS) of the anterior leg compartment have an increased anterior compartment thickness (ACT) compared with control subjects after exertion using ultrasound. Design: Prospective comparison study. Setting: Diagnostic imaging department of a tertiary care hospital. Patients: Four patients with CECS and 9 control subjects. Interventions: Patients with CECS and control subjects ran on a treadmill for up to 10 minutes. Anterior compartment thickness (both groups) and anterior compartment pressure (CECS patients) were measured before exertion and at scheduled intervals after exertion. Main Outcome Measures: Anterior compartment thickness, percentage change in ACT from rest, and compartment pressure. Results: Anterior compartment pressures were diagnostic of CECS using the modified Pedowitz criteria in patients with CECS. Mean percentage change in ACT from rest in patients with CECS versus control subjects at 0.5 minutes was 21.3% versus 6.32% [95% confidence interval (CI), 6.92-35.6 and 0.094-12.5, respectively; P = 0.011]; at 2.5 minutes, it was 24.6% versus 4.22% (95% CI, 10.7-38.5 and 21.85-10.3, respectively; P = 0.003); and at 4.5 minutes, it was 24.9% versus 5.08% (95% CI, 14.3-35.5 and 20.813-11.0, respectively; P = 0.003). Mean ACT in patients with CECS versus control subjects significantly increased after exertion (P = 0.003) at 0.5 minutes, 2.5 minutes, and 4.5 minutes. Conclusions: Ultrasonography reveals a significant increase in ACT in patients with CECS of the anterior leg compartment. Further studies are warranted to validate these findings with the goal of developing anterior leg compartment CECS ultrasound diagnostic criteria and exploring the role of using ultrasound to diagnose CECS in other compartments.